Customize Your Semi-Modular Synthesizer This knob kit is a perfect fit for 6mm diameter knurled pots commonly found on synthesizers, featuring an internal interface to lock the knob in place when assembled—without the need for a set screw. The Moog Knob Kit for Knurled Pots comes with twenty-five (25) knobs in each package, so you can stylize all your favorite Eurorack modules and Moog semi-modular instruments.